Retractable finger bus duct plug with three position handle



P 1961 J. B. CATALDO 3,001,037

RETRACTABLE FIlNGER BUS DUCT PLUG WITH THREE POSITION HANDLE Filed Sept. 13, 1956 2 Sheets-Sheet 1 I i E 35 43 I I 0 fi ;0.s/r/0// 7a 44 I K -3 674 73 fiaJ/T/O/V @j f 73 Z4 1 'INVENTOR. 2 (JOHN acAmL/Ja Par? r/d/v BY Sept 19, 1961 J. B. CATALDO RETRACTABLE FINGER BUS DUCT PLUG WITH THREE POSITION HANDLE Filed Sept. 13,1956

2 Sheets-Sheet 2 L J A m 5 mm 5 m m 7 VA A m 4 1 M A N H A w M V. B x w 4 L v 5 2 w 4 United States Patent RETRACTABLE FINGER BUS DUCT PLUG WITH THREE POSITION HANDLE John B. Cataldo, Birmingham, Mich., assignor, by mesne assignments, to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed Sept. 13, 1956, Ser. No. 609,590 13 Claims. (Cl. 200-50) My invention relates to bus duct plugs associated with plug-in bus ducts and more particularly to plugs having retractable bus contact fingers, with a single control handle to perform both load switching and positioning of the contact fingers.

In present bus duct plugs, the contact fingers are fixed in relation to the plug case and project from the plug case, thus exposing the fingers to damage in transit or during installation and requiring additional storage space for the plug. The operator is exposed to the danger of electrical shock as he attempts to locate the fingers in the duct opening.

Further danger of shock is present when the plug cover is open while the contact fingers are engaging the bus. With projecting fingers there is also the problem of arcing at the bus when the plug is being installed or disconnected at times when the load is electrically connected to the plug. I

Although recent developments in this field provide plug-in units with retractable fingers, control of these fingers is achieved only by opening the plug cover. That is, these plugs having retractable fingers rely on th cover to control contact finger positioning and furthermore, do not maintain high pressure contact with the bus during load switching.

My invention solves these problems by utilizing a duct plug having a single rotary control handle mounted on the plug cover. The control handle is selectively and operatively connected to retractable conducting contact fingers and also to the operating mechanism of the disconnect contacts.

A manually operated button or latch on the handle is used to perform the selecting operation. Thus, although the retractable conducting finger and disconnect contacts are electrically connected in series, they are mechanically independent, and hence, can be controlled by the handle in a predetermined sequence so that the conducting fingers must contact the bus bars before the cooperating contacts are engaged and the cooperating contacts must disengage before the conducting fingers can break contact with the bus bars and be withdrawn into the plug casing.

The primary object of my invention is to provide a plug-in unit for a plug-in bus duct system having retractable conducting fingers in series with disconnect contacts which are selectively connected to an operating handle to provide a predetermined sequence of operation.

The operating handle operates between a first, second and third position. When the handle is operated between the first and second positions it directly mechanically drives the conducting fingers. When the handle operates between the second and third positions the drive to the conducting fingers is broken and the handle now operates the mechanism that controls the disconnect cooperating contacts. 7

Another object of my invention is to provide a bus plug having ease and simplicity of operation which is achieved by a single rotary handle.

A further object of my invention is to provide a second latch means which prevents the plug cover from opening while the plug is electrically connected to the bus.

Another object is to provide retractable, positive act- Patented Sept. 19, I961 high pressure engagement ofthe contact fingers with the bus is unaffected during load switching.

Still another object is to provide means whereby the operator may perform load switching very conveniently, but may not inadvertently disconnect the contact fingers from the bus duct conductors.

Still another object is to provide a third latch means to hold the conducting fingers in contact with the bus bars after engagement is established.

These and other objects of the invention will be apparent from the following description when taken in connection with the drawings in which:

FIGURE 1 is a section taken along the line 1--1 in the direction of arrows 1-1 of FIGURE 4. This view is shown with the operating handle in the On position.

FIGURE 2 is a section taken along the line 22 in the direction of arrows 22 of FIGURE 4, and shows the finger positioning mechanism when the operating handle is in either the Off (second position) or On (third position), at which time the conducting fingers remain in their second position as illustrated.

FIGURE 3 is also a section taken in the direction of the arrows 2-2 of FIGURE 4 and shows the finger positioning mechanism when the operating handle is in the Disconnect position (first position), at which time the conducting fingers remain intheir first position as illustrated.

FIGURE 4 is a section taken along line 4-4 in the direction of arrows 4-4 of FIGURE 1, with the control handle in the Off position, the'handle being shown in phantom.

FIGURE 5 is a diagrammatic presentation of a complete system from the generator to the load.

The drawings illlustrate a three-phase system. However, this invention 'is adaptable equally well to a Single phase system or a system having any number of phases by merely providing, for each phase, a conducting finger, a pair of cooperating contacts and a terminal for the output connection, the components of each phase being simultaneously operated.

Referring to FIGURE 5, a bus duct plug 60 is installed on the housing 61 of a plug-in bus duct 64 with the contact fingers 47 of the plug 60 engaging the bus bars 16. The bus bars 16 are in turn connected to the source of electrical energy 76.

The function of the bus duct plug 60 is to complete the electrical path between cable 62 and the bus bars 16.

This is accomplished by passing the cable 62 through the knockout 74 (FIG. 1) in the end of the plug case 55. The cable conductors are connected to load terminals 37 of the load swtich 80, which may be a disconnect contact head of the type disclosed by Patent No. 2,302,849. To the load terminals 37 of the load switch are connected one end of pigtails 33 whose other ends are connected to the contact fingers 47 at terminals 57. The contact fingers 47 are projected through the opening 58 in the bottom of the case 55 and through an opening in the duct housing in alignment with plug opening 58 so that conducting fingers 47 contact the bus conductors 16. The electrical path is completed when the disconnect switch 80 is On which electrically connects load terminals 37 to line terminals 38.

In order to mount the plug 60 to the duct housing 61,

button hook shaped slots 75 are cut in the duct housing 61. Screws 70' having left hand threads are mated with tapped holes 72 in the mounting flanges 56 that project from the ends of the plug 60 in the plane with the bottom of the plug. The large heads 7 10f the screws 70" are passed through the large openings'*of the button hook shaped holes 75. Then the plugi'60is moved in the direc Q rotary control handle 42 is mounted'on the cover 45. A

manually operated button 17 biased-upwardly"by' the coil spring 18 is mounted on the handle-:4z-'and permits the handle 42 to be moved betwentheOri-Oit positions only, unless the button 17 isdepressedg to perform load switching by means of an operative connection to the load switching mechanism 70 whichin -turncont'rls' engagernent between the cooperating contacts that form part of the disconnect contact head 80.1 I

In order to move the control handle 42from' its second or Oif position to its first or Disconnect position, the I manually operated button 17 must'be depressed. Depressing the button 17 against the bias of spring 13 operatively connects thehandle 42 to thecontact holder 46, in which are mounted the contact fingers 47, so that the position of the fingers 47 can be directly controlled by the handle 42. That is, at times when the button 17 is depressed, a direct mechanical drive is established between the handle 42 and the conducting fingers 47. This means that when an operator turns the handle to the Disconnect position, he can be sure that the fingers 47 are not contacting the bus bars 16 and the plug 60is deencrgized.

In FIGURE 1, the bus duct plug 60 consists of a case 55 having a cover 45 which is pivotally mounted to the case 55 by hinge 36. The control handle 42 consists of a-lower section 51, upper sections 53 and inclined sections 52 joining sections 53 to 51. Holes 54 are cut in portions 53 to permit operation from the ground, or other remote position, by means of an extension; Handle 42 is pivotally connected to the outside of the cover 45by securing means 32 which may be a rivet or other suitable connection which projects through the cover 45 and serves to guide operating member 41 and disconnect member 44. Screws 26 and 27 pass through arcuate slots 28 and 29 cut in the cover 45, serving to connect member 41 to the handle 42 sothatthey move in unison. A finger 43 projects downwardly from operating member 41 to engage the load switch operating mechanism 70, that is affixed to the side of the case 55. Rotating the handle42 from the Oil to On positions moves the 'finger 43 from right to left in FIGURE 1 causing the operating! mechanism 70' to bring the cooperating contactsinto engagement, the cooperating contacts being part of the load switch 80 electrically connecting the load terminals 37 to the line terminals 38 of the load switch 80. Disconnect switch 80'is mounted on insulating block 94?, which is affixed to the bottom of the case 55. Movement of the handle 42 between On and Ofl. positions does not effect the high pressure contact between the conducting fingers 47 and the bus bars 16. That is, the fingers 47 remain in their second position, as illusstrated in FIGURES 1 and 2, during this movement of handle 42.

Interlock angle projects from the side of the case 55 and serves to prevent the cover 45 from being opened or closed unless the handle 42 is in the Fingers'Disconnect position. On attempting to: close the cover 45, finger 43 will strike interlock angle 25 unless the control handle 42is in Disconnect position. Should'the operator attempt to open the'cover 45, the top of member 41-will strike the interlock angle 25, unless the control handle 42 is in the Disconnect position-.- A finger operated button 17 located on the handle 42 is biased upwardly'by means of spring 18. This button 17 is connected to a narrow body 34 which has an enlarged head 19 at its.

opposite end. The head 19 travels in the large arcuate slot 21 cut in the cover 45 and serves to limit the travel of the control handle 42 between the On-Ofi' positions.

With the handle 42 in the Off position, the button 17 may be depressed since it is now aligned above hole 20 in the disconnect member 44;with the enlarged head 19 mating with hole 20. At this time the handle 42 may be moved to the Fingers Disconnect position with the nar' row body 34 travelling in the reduced portion 23 of the arcuate slot in the cover 45. The thin lip 19a at the bottom of head 19 is so sized that it can'pass through hole 20 in member 44 and a similar hole in member 41. However, theoutside diameter of lip 19a is larger than the width of slot 21 so that while'head It? may enter slot '21 lip 19 cannot pass therethrough.

A projection 15, shown in FIGURE 2, extends downwardly from one end of the disconnect member44, so 7 that the vertical slot 14 in projection 15 mates with pin 13 projecting from one end of actuator 10. Actuator it? being pivotally mounted to the end of the ca'se by means of rivet 11. On the other end of actuator 10; is mounted pin 12, which travels in the raceway 31 formed by the FIGURE 2 with theedge 78 of slot 14bearing against pin- 13 which in turn rotatesactuator '1!) in a counterclockwise direction raising the contact holder 46 and retracting thecontact fingers 47 and insulators 57 through the opening. 53 in the bottom of the case 55 (FIGURE 3). Engagementof the contact fingers 47 and the bus 16 is shown to be by butt contact. However, those skilled the art Will readilyv see'that Contact can be made by frictional engagement to bus bars mounted edgewise.

The contact holder 46 is pivotally connected to the case 55 through arms 35 which pivot on pins 4'3. Pins 48 project into the case 32 from its sides. Springs 49 bear against'arms 35 biasing the contact holder 46 in an upward direction, as shown in FIGURE 1.

In the On and Off positions, the'contact holder 46 is locked in its down'position by the action of springs 49 biasing the holder 46 upward against pin 12 and urging actuating member 14) in a clockwise direction, FIGURE 2.

Cover catch 24 projects upwardly from the end oi the case 55 and mates with slot 36 in the cover 45 thus preventing the cover from accidentally fiyingopen when the handle 42 is in the Disconnect position.

To summarize plug opera-tics: after the plug is aflixcd to' the duct, beginning with the cover opened:

In'oi'de'r'to close the cover 45, the control handle 42 must be'in Disconnect position, orfelse the cover interlock 25 and '41 will prevent closing of the cover. The cover 45 is now closed and the handle 42 is rotated to'the Oif position. The cover 45 cannot be opened now. When the handle 42 reaches the Off position, the spring .18 raises the button 17. The contact fingers 47 have been projected from the plug 60 and are now in engagement with the duct conductors 16'.

The handle is now rotated to On, this causes the load operating mechanism 78 to closethe load switch {it engaging its cooperating contacts and energizes the load 63..

Rotating the handle 42 between'the On and Off positions, merely operates the load switch 80 the position of the contact fingers 4'7 being unaffected thereby.

The handle 42 is new'rnoved backto the Off position,

it about its 1 in the foregoing, I have described my invention only in connection with preferred embodiments thereof. Many variations and modifications of the principles of my invention within the scope of the description herein are obvious. Accordingly, I prefer to be bound not by the specific disclosure herein, but only by the appending claims.

' I claim: a a

l. A plug-in unit for a bus duct system being comprised of a housing, a handle, disconnect means, a conducting finger; s'aidhousing being comprised of a casing having a cover; said operating handle being operatively mounted on saidcover; said disconnect means being comprised of a pair of cooperating contacts and an operating mechanism; said operating mechanism operatively associated with said cooperating contacts for moving said cooperating contacts into engaged and disengaged position; a latch means operatively associated with said handle for selectively connecting said handle to said conducting finger; said operating handle having a first, second and third position; said latch means being'operative to connect said handle to said conducting finger when said handle is moved from said first to said second position and operative to disconnect said handle from said finger when said handle is moved between said second and said third position; said operating mechanism of said disconnect means being. positioned for engagement by said operating handle only when said operating handle is moved from said second to said third position and when said operating handle is moved from said third to said second position to thereby move said cooperating contacts to said disengaged position; said conducting finger being positioned to operatively engage an electrical conducting means disposed externally of said casing when said operating handle is in said second position.

2. A plug-in unit for a bus duct system being comprised of a housing, a handle, disconnect means, a conducting finger; said housing being comprised of a casing having a cover; said operating handle being rotatably mounted on said cover; said disconnect means being comprised of a pair of cooperating contacts and an operating mechanism; said operating mechanism operativelyassociated with said cooperating contacts for moving said cooperating contacts into engaged and disengaged position; a first latch means operatively associated with said handle for selectively connecting said handle to said conducting finger; said operating handle having a first, second and third position; said first latch means being operative to connect said handle to said conducting finger when'said handle is moved from said first to said second position and operative to disconnect said handle from said finger when said handle is moved between said second and said third position; said operating mechanism of said disconnect means being positioned for engagement by said operating handle only when said operating handle is moved from said second to said third position and when said operating handle is moved from said third to said second position to thereby move said cooperating contacts to said disengaged position; said conducting finger being positioned to operatively engage an electrical conducting means disposed externally of said casing when said operating handle is in said second position; a second latch means, said second latch means being unlatched when said handle is in said first position; said second latch means constructed to prevent the opening of said cover when latched.

3. A plug-in unit for a bus duct system being comtion; a latch means operatively associated with said handle for selectively connecting said handle to said conducting finger; said operating handle having a first, second and third position; said latch means being operative to connect said handle to said conducting finger when said handle is moved from said first to said second position and operative to disconnect said handle from said finger when said handle is moved between said second and said third position; said operating mechanism of said disconnect means being positioned for engagement by said operating handle only when said operating handle is moved from said second to said third position and when said operating handle is moved from said third to said second position to thereby move said cooperating contacts to said disengaged position; said casing having an opening, said conducting finger positioned in alignment with said opening, said conducting finger having a first and second position; said latch means operatively connecting said operating handle to said conducting finger to thereby move said conducting finger from its said first to said second position when said operating handle is moved from its said first to said second position; said first latch means automatically unlatched when said handle is moved from said first to said second position to thereby disconnect said operating handle fromsaid conducting finger to permit said conducting finger to remain in its said second position when said handle is moved between its said second to said third position; said conducting finger when in its said second position being at least partially projected through said opening.

4. A plug-in unit for a bus duct system being comprised of a housing, a handle, disconnect means, a conducting finger; said housing being comprised of a casing having a cover; said operating handle being rotatably mounted on said cover; said disconnect means being comprised of a pair of cooperating contacts and an operating mechanism; said operating mechanism operatively associated with said cooperating contacts for moving said cooperating contacts into engaged and disengaged position; a first latch means operatively associated with said handle for selectively connecting said handle to said conducting finger; said operating handle having a first, second and third position; said latch means being operative to connect said handle to said conducting finger when said handle is moved from said first to said second position and operative to disconnect said handle from said finger when said handle is moved between said second and said third position; said operating mechanism of said disconnect means being positioned for engagement by said operating handle when said operating handle is moved from said second to said third positionand when said operating handle is moved from said third to said second position to thereby move said cooperating contacts to said disengaged position; said casing having an opening, said conductin'g finger positioned in registry with said opening, said conducting finger having a first and second position; said conducting finger being contained within the confines of said casing when in its said first position and being moved into high pressure contact engagement with bus bar of a bus duct when in its said second position; said first latch means operatively connecting said operating handle to said conducting finger to thereby move said conducting finger from its said first to said second position when said operating handle is moved from its said first to said second position; said latch operatively disconnecting said operating handle from said conducting finger to thereby permit said conducting finger to remain in said second position when said handle is moved between said third and said second positions.

5. A plug-in unit for a bus duct system being comprised of a housing, a handle, disconnect means, a conducting finger; said housing being comprised of a casing having a cover; said operating handle being operatively mounted on said cover; said disconnect means being comprised of a pair of cooperating contacts and an, Operating mechanism; said operating mechanism operatively associated with said cooperating contacts formoving said cooperating contacts into engaged and disengaged posifrom said second: to said third position and when said operating handle is moved from said third to said second position to thereby move said cooperating contacts to said disengaged position; said casing having an opening, said conducting-finger positioned'in alignment with said opening, saidconducting-finger having a'first and second position;.said latch means operatively connecting said operating handle'to said conducting finger to thereby move said ,conductingfinger from its said first to its said second position when said operating handle is moved from its 'said'firstto its said second position; said conducting finger when in its said second position being at least partially projected through said opening; said first latch operatively disconnecting said operating handle from said conducting finger tothereby permit said conducting finger to remain in its said second position when said handle is moved between said third and said second positions; biasing means -to-bias said condu'cting'finger toward its said-firstposition.- i s 6; A plug-in unit for a bus duct system beingcom: prised of a housing, a handle, disconnect means, a conducting finger; said housing being comprised of a casing hav-- ing a cover; said operating handle being rotatably mounted on said cover; said disconnect means being comprised of a'pai-r'of cooperating contacts and an operating mech- I anism said operating'rnechanism operatively associated with said cooperating contacts for moving said cooperating contacts into engaged and disengaged position; a first latch means operatively associatedwith said handle for selectively connecting: said handle to said conducting finger; said operating handle having a first, second and third position; said first latchmeans being operative to connect said handle to said conducting finger when said handleis moved from said first to said second position and operative to disconnect said handle from said finger when said handle ismoved between said second and said third position;said operating mechanism of said disconnect means being positioned for engagement by said operat ing handle only when said operating handle is moved from said second to said third position and when said operating handle is moved from said third to said second position to thereby move said cooperating contacts to said disengaged position; said casing having an'opening, said conductingfinger positioned in alignment with said opening, said conducting finger having a first and second position'; said conducting finger when in its said second position being at least partiallyprojected through'said opening; said'first latch means operatively connecting said operatinghandle to said conducting finger to thereby move said conducting finger from -its said first to said second position when said operating handle is moved from its said firstto' its "said second position; said first latch operatively-diseonnecting said'operating handle-from said con ducting finger to' thereby permit said conducting finger to remain in its said'second position when said handle is moved between its said third and its said second positions; biasingrneans to bias said conducting finger toward its said first position; a second latch means comprised of an over-center device to retain said conducting finger in its'sa'id second position against the force of said biasing means while said handle is being moved between its said second and its said third positions.

7. A plug-in unit for a bus duct system being com prised of a housing, a handle, disconnect means, a conducting finger; said housing being comprised of a casing having a cover; said operating handle being operatively mounted on said cover; said disconnect means being comprised of a pair of cooperating contacts and an'operating mechanism; said operating mechanism operatively as sociated with said cooperating contacts for moving said cooperating contacts into engaged and disengaged position; a first latch means operatively associated with said handle for selectively connecting said handle to said conducting finger; said operating handle having a first, second and third position; said first latch means being operative to connect said handle to said conducting finger when said handle is moved from said first to said second position and operative to disconnect said handle from said finger when said handle is moved between said second and said.

third position; said operating mechanism of said disconnect means being positioned for engagement by said operating handle only when said operating handle is moved from said second to said third position and when said operating handle is moved from said third to said second position to thereby move said cooperating contacts to said disengaged position; said conducting finger being in elec trical series with one of said cooperating contacts; said conducting finger having a first and second position; said first latch means operatively connecting said operating handle to said conducting finger to thereby move said conducting finger from its said first to said second position when said operating handle is moved from its said first to its said second position; said first latch operatively disconnecting said operating handle from said conducting I finger to thereby permit said conducting finger to remain in its said second position when said handle is moved between its said third and its said second positions; biasing means to bias said conducting finger to its said first position; a second latch means being comprised of an over-center device to retain said conducting finger'in its said second position against the force of said biasing means while said handle is being moved between itssaid second and its said third positions; a fourth means to defeat said second latch means when said handle is moved selectively connects to said conducting finger and'said. second extension is selectively connected to said disconnect means; said disconnect means being comprised of a pair of cooperating contacts associated with an operating mechanism; said conducting finger being in electricalseries with one of said cooperating contacts; said operating a handle having a first, second and third position;'a first.

latch means operative when latched to connect said handle to said conducting finger only when said handle moves between said first and second positions and operative when unlatched to connect said handle to said operating mechanism when said handle moves between said second and said third positions; a second latch means being defeated to permit said cover to be opened when said handle is in said first position and operative to prevent said cover from being opened when said handle is in said second and third positions. 7

9. A plug-in unit for a plug in bus duct system comprised of a housing, a first means, a second means, a control device, a third means to selectively connect and disconnect said first and said second means to said control device; said control device having a first, second, and third position;lsaid firstrmeans being operatively connected to; said control device only when said controldevice is-opr;

erated between said first and said secondfposition's; said second means being operativelyconnected to said control device only when said control device is operated between said second and said third positions; said first means being comprised of a contact holder anda' conductingtfinger mounted in said'holder; said secondmans being comprised of a pair of cooperating contacts and an operating mechanism operatively connected to said cooperating contacts so as to cause engagement and disengagement of said cooperating contacts; said conducting finger being in electrical series with one of said cooperating contacts.

10. A plug-in unit for a plug-in bus duct system being comprised of a housing, a control handle, a disconnect means, conducting fingers; said housing being comprised of a casing having an opening and a cover; said control handle being rotatably mounted on said cover; said control handle having a first, second, and third positions; said disconnect means being comprised of a pair of cooperating contacts and an operating mechanism; said operating mechanism being operatively associated with said cooperating contacts so as to move said cooperating contacts into engagement and disengagement; said cooperating contacts being electrically connected to said conducting finger; a first latch means to selectively connect said control handle to said conducting finger; said first latch means being operative to connect said handle to said finger only when said handle is being moved between said first and said second positions and operative to disconnect said handle from said finger when said handle is being moved between said second and said third positions; said operating mechanism of said disconnect means being positioned for engagement by said operating handle when said operating handle is being moved between said second and said third positions and positioned for disengagement of said cooperating contacts when said handle is moved from said third to said second position; a second latch means, said second latch means being unlatched only when said control handle is in said first position; said second latch means being constructed to prevent the opening of said cover when latched; said conducting fingers being positioned in alignment with said case opening, said conducting finger having a first and second position; said conducting finger when in its said second position being at least partially projected through said opening; said first latch means operatively connecting said handle to said conducting finger to thereby move said conducting finger from its said first to its said second position when said operating handle is moved from its said first to its said second position, said conducting finger remaining in its said second position as said handle is moved between said second and said third positions; a biasing means to bias said conducting finger toward its said first position; a third latch means to retain said conducting finger in its said second position against the force of said biasing means while said control handle is being moved between said positions two and three; said first latch means servingto prevent movement of said control handle between its said second and its said first positions while said latch means is unlatched.

11. A plug-in unit fora multi-phase bus duct system being comprised of a housing, a control handle, a conducting finger for each phase, a pair of cooperating contacts for each of said fingers, an operating mechanism to bring said cooperating contacts into engagement and dis"- engagement, a first latch means operatively associated with said handle for selectively connecting said handle to said conducting fingers; said operating handle having a first, second and third positions; said first latch means being operative to connect said handle to said conducting fingers when said handle is moved between said first and second positions and operative to disconnect said handle from said fingers when said handle is being moved be tween said second and said third positions; said operating mechanism associated with said cooperating contacts being so positioned for engagement by said operating handle only when said operating handle is moved from said second to said third position. and when said operating. handle is moved from said third to second position to thereby move said cooperating contacts to disengage position; the conducting finger of each phase being 'inelectrical series with one of the cooperating contacts of that phase.

12. A plug-in unit for a multiphase bus duct system being comprised of a housing, a handle, disconnect means, for each phase of said unit phase system conducting fingers; said housing being comprised of a casing having a cover; said operating handle being operatively mounted on said cover; each of said disconnect means being comprised of a pair of cooperating contacts; an operating mechanism; said operating mechanism operatively associated with each of said pair of cooperating contacts for simultaneously moving said cooperating contacts into engaged and disengaged position; a first latch means operatively associated with said handle for selectively connecting said handle to each of said conducting fingers; said operating handle having a first, second and third position; said first latch means being operative to connect said handle to each of said conducting fingers when said handle is moved from said first to said second position and operative to disconnect said handle from each of said conducting fingers when said handle is moved between said second and said third position; said operating mechanism of each of saiddisconnect means being positioned for engagement by said operating handle only when said operating handle is moved between said second and said third position to thereby simultaneously move each of said cooperating contacts between said engaged and disengaged positions; the conducting finger of each phase being in electrical series with one of the cooperating contacts of that phase.

13. A plug-in unit for a bus duct system'being comprised of a housing, a handle, disconnect means, a conductingfinger; said housing being comprised of a casing having a cover; said operating handle being operatively mounted on said cover; said disconnect means being comprised of a pair of cooperating contacts and an operating mechanism; said operating mechanism operatively associated with said cooperating contacts for moving said cooperating contacts into engaged and disengaged position; a latch means operatively associated with said handle for selectively connecting said handle to said conducting finger; said operating handle having a first, second and third position; said latch means being operative to connect said handle to said conducting finger when said handle is moved from said first to said second position and operative to disconnect said handle from said finger when said handle is moved from said second to said third position; said handle being positively and mechanically linked to said'finger when said handle moves between its said first and second positions to positively drive said finger; said operating mechanism of said disconnect means being positioned for engagement by said operating handle only when said operating handle is moved from said second to said third position and when said operating handle is moved from said third to said second position to thereby move said cooperating contacts to said disengaged position; said casing having an opening, said conducting finger positioned in alignment with said opening, said conducting finger having a first and second position; said first latch means operatively connecting said operating handle to said conducting finger to thereby move said conducting finger from its said first to said second position when said operating handle is moved from its said first to said second position; said conducting finger being contained within the confines of said casing when in its said first position and being moved into high pressure contact engagement With bus bar of a bus duct when in its said second position; said latch means automatically unlatched when said handle is moved from said first to said second position to thereby disconnect said operating handle from said conducting finger to permit said conducting finger to remain in its said second position with high pressure engagement .of the bus bar being -maintained when said handle is moved betwen'its said second to said,

1,798,244 'woodworth Mar. 31 193 mic 104,937

,rAnderson at al. "1., Mq a s a Constantino e1: 211; .o

Jan. 13, 1948 -i Mar. 26, 1957 June 20, 1950'" Apr. 24; 1951 

